Frequencies for first 10,000 rows of dr_train variable in vehicle dataset :

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        690        6.90        6.90
          1 |        334        3.34       10.24
          2 |         49        0.49       10.73
          3 |          4        0.04       10.77
          4 |          1        0.01       10.78
          5 |         10        0.10       10.88
          9 |      8,912       89.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016